You can certainly wind the jaws outside the body diameter and hold work at least the same diameter as the body. However, if you are looking at typical lathe chucks, do you realise how heavy these things are? I have 200mm 4-jaw chucks for my lathe (metal-working) and it ideally needs two hands to comfortably lift and fit it. Up to 300mm and you are getting to the point of needing a hoist to move it.